A conventional scroll fluid machine is formed by, for example, as shown in FIG. 1, a fixed scroll 10 having a first wrap 14 formed inside a recessed space s enclosed by a peripheral wall 12, and a movable orbiting scroll 20 having a second wrap 24 configured to interleave with the first wrap 14, and is configured to be capable of changing the volume of sealed pockets formed between the wraps 14 and 24 by revolving the orbiting scroll 20 around the fixed scroll 10 without rotating the orbiting scroll 20.
The orbiting scroll 20 is revolved by a revolving mechanism that includes a main drive crankshaft 42 coupled to the orbiting scroll 20 via an integral eccentric shaft 44 made eccentric to the orbiting scroll 20 by an amount corresponding to the orbiting radius, this main drive crankshaft 42 being rotatably supported along a center axis of a housing 40 and rotated, to impart a revolving motion of the orbiting scroll 20. Anti-rotation systems 50 each having a driven crankshaft 52 that undergoes an eccentric rotation with an eccentric amount corresponding to that of the main drive crankshaft 42 are provided at a certain distance in the radial direction from the center axis of the main drive crankshaft 42, symmetrically in the circumferential direction.
This anti-rotation system 50 prevents rotation of the orbiting scroll 20 while allowing it to revolve as the main drive crankshaft 42 rotates. The driven crankshaft 52 is rotatably supported by a first roller bearing 54 secured in the housing 40, and an eccentric shaft 52a integral with the driven crankshaft 52 is rotatably supported by a second roller bearing 56 that is supported by the orbiting scroll 20.
In scroll fluid machines, particularly in compressors, to achieve clean compressed gas, a spiral self-lubricating seal member 30 is fitted in a groove recessed in the end face of the second wrap 24 of the orbiting scroll 20 contacting the fixed scroll 10, and in the end face of the first wrap 14 of the fixed scroll 10 contacting the end plate 22 of the orbiting scroll 20. Thus, while the wraps are maintained oil-free, the inside of the recessed space s is kept tightly sealed from the outside.
In oil-free scroll fluid machines, the orbiting scroll 20 is adjusted to achieve precise parallelism and a clearance relative to the fixed scroll 10 to revolve with adequate interleaving precision. This is for preventing various problems such as leakage from the recessed space s, noise caused by contact between a wrap and the sliding surface of the counterpart, abnormal abrasion, increase in power due to a wrap contacting on one side, and durability loss of bearings, etc. Oil-free scroll fluid machines commonly rely on sealed grease as they do not have means of lubricating the bearings of the main drive crankshaft 42 and driven crankshafts 52. With this sealed grease, however, the grease-sealed part need to be replenished with grease periodically.
Patent Document 1 (Japanese Examined Utility Model Application Publication No. H7-2961) discloses means of replenishing grease for a bearing 46 rotatably supporting an eccentric shaft 44 of the main drive crankshaft 42. This grease replenishing means has an oil supply passage 60 drilled from an outer circumferential surface of a balance weight 48 attached to the eccentric shaft 44 and opens to a shaft end of the eccentric shaft 44, as shown in FIG. 1. The opening of the oil supply passage 60 at the shaft end of the eccentric shaft is brought opposite a bearing plate 26 attached to the orbiting scroll 20 to communicate with the bearing 46 through a gap c formed between the eccentric shaft end and the bearing plate 26.
To replenish grease, the opening of the oil supply passage 60 at the outer circumferential surface of the balance weight is brought opposite a grease gun port formed in the housing 40, and grease is replenished through the oil supply passage 60 from a grease gun inserted into the grease gun port.
Patent Document 2 (Japanese Patent Application Laid-open No. 2002-227779) discloses two means of replenishing grease for a first roller bearing 54 and a second roller bearing 56 that form an anti-rotation system 50. This replenishing means will be described with reference to FIG. 1. Referring to FIG. 1, the first replenishing means is an oil supply passage drilled in the driven crankshaft 52 along the axial direction to open to the inside of a bearing holder 70 at one end and to a slit gap c formed between the second roller bearing 56 and the bearing plate 26 at the other end. A grease nipple is mounted to the opening at the bearing holder 70 to supply grease to the first roller bearing 54 and the second roller bearing 56 through the oil supply passage.
The second replenishing means disclosed in Patent Document 2 is a second oil supply passage, in addition to the oil supply passage described above, drilled in the housing 40 that supports the first roller bearing 54 in a direction orthogonal to the scroll axis from a radially outer side of the first roller bearing 54. The second oil supply passage passes through the first roller bearing 54 and communicates with the previously mentioned oil supply passage. A grease nipple is mounted to the second oil supply passage for injecting grease.
The grease replenishing means disclosed in Patent Document 3 (Japanese Patent Application Laid-open No. 2005-282496), which will be explained with reference to FIG. 1, is means of injecting grease into the bearing 46 from the fixed scroll side, via a through hole formed in a central portion of the end plate 22 of the orbiting scroll 20. Also disclosed is means of injecting grease into the second roller bearing 56 via a through hole formed in the bearing plate 26 that supports the second roller bearing 56 at a position outside the orbiting scroll 20.
Patent Document 1: Japanese Examined Utility Model Application Publication No. H7-2961
Patent Document 2: Japanese Patent Application Laid-open No. 2002-227779
Patent Document 3: Japanese Patent Application Laid-open No. 2005-282496
Patent Document 2 discloses means of replenishing grease to the first roller bearing 54. However, with the first replenishing means disclosed in Patent Document 2, the bearing holder 70 needs to be removed, and a grease nipple needs to be mounted to the opening at the bearing holder 70, to replenish grease. Since a pulley 100, a cooling fan 104, and a cooling fan cover 106, etc. are attached at the other end of the main drive crankshaft 42 as shown in FIG. 1, these components need to be removed to set a grease gun on the pulley 100 side.
The second replenishing means disclosed in Patent Document 2 requires extra space on the radially outer side of the housing 40 for installing the grease gun. The second oil supply passage is drilled in a direction orthogonal to the axial direction of the scroll, and oriented at right angle with the oil supply passage drilled in the driven crankshaft 52. Therefore, these oil supply passages cannot be formed at the same time with a cutting machine, and an extra number of process steps is required.
When replacing the self-lubricating seal members 30 mentioned above in scroll fluid machines, it is necessary to remove the fixed scroll 10 from the housing 40. It is desirable if, at this time, grease can also be supplied to the first roller bearing 54.